1. Field of the Invention
The present invention relates to an automatic focus detecting device for automatically detecting a focus condition of an object, and more particularly, to an apparatus having such automatic focus detecting device.
2. Description of the Related Art
An apparatus having an automatic focus detecting function is conventionally known. For use in such apparatus, various automatic focus detecting devices have been proposed which have a plurality of detecting areas for detecting a focus condition of an object corresponding to those areas in order to more effectively use an automatic focusing function.
For example, a conventional camera is provided with focus detecting areas at the center and right and left sides thereof in an image area to be photographed. A photographer uses this camera by manually selecting a focus detecting area suitable for the position of a main object in the image area among the above-described plurality of focus detecting areas. A focus condition of the object is detected by using the selected focus detecting area in such conventional camera, so an operation of changing a composition after a focus lock is eliminated more than in such a camera as having only one focus detecting area.
With a conventional camera held its longitudinal side in parallel with the horizontal direction (the camera is held horizontally) for photographing, a main object is more likely to be located at an upper part of the center of an image area to be photographed. Therefore, the photographer should once set the object at the center of the image area for a focus detection and then, set the camera anew so that the object is located at the upper part of the center, which make the operation of the camera troublesome. In order to overcome such problem, disclosed in, for example, the patent application Ser. No. 581,886, filed Sep. 13, 1990 and assigned to the same assignee of the present invention, is a camera in which an additional focus detecting area is provided at an upper portion of the center, so focus detecting areas are symmetrical only in a horizontal direction when the camera is held horizontally.
While the above-described conventional camera eliminates the operation of changing a composition after a focus lock, it is not sufficiently practical in use. For example, there occurs photographing with a camera held vertically or horizontally depending on an object. In such a case, a focus detecting area where a main object is often positioned varies depending on the camera situation. Therefore, an operation for selecting an appropriate area might not be carried out effectively when the focus detecting areas are designated one by one in the same order at all times irrespective of the possibility that an area includes the main object at the selection of one of the plurality of focus detecting areas.